Fiber conduit



p 14, 1931. w, G. JOHNSON FIBER CONDUIT Filed Nov. l5, 1929 Patented Apr. 14, 1931 UNITED STATES PATENT OFFICE WILLIAM G. JOHNSON, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO LINE MATERIAL COMPANY, OF SOUTH MILWAUKEE, WISCONSIN, A OORIORATION OF WISCONSIN FIBER CONDUIT Application led November 15, 1929. Serial No. 467,447.

The invention relates to fiber conduit and has for its object to provide a fiber conduit of a laminated construction whereby the conduit possesses sufficient compressive strength to resist crushing and at the same time possesses ductility to resist shocks imposed upon it in'handling and in service.

Heretofore fiber conduits have been made from pulpbers pressed andv formed into shape which conduits possess ductility or resistance to shock but which do not possess the requisite compressive strength to resist crushing. Heretofore also fiber conduits have been formed entirely of laminated sheet pulp construction which have the desired tensile strength but are brittle and do not possess the required ductility for most efficient use in service.

According to the present invention a fiber conduit of laminated construction is produced in which the inner layer is formed of pressed pulp fiber, providing the requisite ductility, and this inner layer is surrounded by a number of plies of laminat-ions of sheet pulp, giving to the product the desired tensile strength. Preferably the fibers of the inner layer are heterogeneously arranged, that is, they run in all directions, while the fibers forming the sheets or laminated outer layer are arranged so that they extend mainly in two directions, namely, lengthwise and axially of the tube with the greater number extending axially, forming a sheet construction of high tensile strength and which upon drying compress the fibers of the inner layer closer together to form a more` efficient tube construction than those heretofore proposed.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings Fig. l is a vertical, sectional view of a finished ber conduit embodying the invention, parts being broken away;

Fig. 2 is an end view of the conduit with parts broken away and parts shown in section.V p

Referring to the drawings the numeral 3 designates the inner layer, formed of pressed pulp fibers in which the fibers extend heterogeneously or in all directions, and 4 the outer portion of the conduit formed of a number of plies or laminations 5 which are wound about tbe pressed pulp layer 3. In each of these laminations 5 the majority of the interlocked fibers are disposed lengthwise and axially of the conduit with the greatest number lying axially of the conduit. When a conduit with the layers disposed as above described is dried to form the finished product the outer sheet layers 5 contract about the inner layer 3 and compress the same and act to bring the fibers thereof closer together.

With the above construction the inner layer 3 gives to the conduit the desired ductility to resist shock while the outer portion, formed by the superimposed sheets 5, imparts to the material the desired tensile strength to resist cracking.

The fiber conduit above described is particularly useful for electrical installations although it may be used for other purposes.

I desire it to be understood that this invention is not to be limited to any particular form or arrangement of parts except insofar as such limitations are included in the claims.

W'hat I claim as my invention is:

1. A laminated fiber conduit comprising a pulp body portion having the fibers arranged to provide ductility, and a reinforcing portion having the fibers arranged to impart tensile strength to the conduit and compress the fibers of the body portion.

2. As an article of manufacture, a fiber conduit having an inner body portion of pressed pulp fiber and an outer body portion formed of fiber sheet laminations.

3. In a fiber conduit, an inner body portion of pressed pulp fibers having the fibers thereof running in all directions, and a reinforcing layer for said inner body portion formed of fiber laminations wound about said inner body portion.

4. In a fiber conduit, an inner body portion of pressed pulp fibers having the fibers thereof running in all directions, and a reinforcing laminated la er for said inner body Y portion formed of a ber'sheet'wound about said inner bodyjportion; the fibers of said sheet disposed tov run mainly lengthwise and 5 axially of the conduit. e l

. 5. --In a fiber conduit', an inner body 'gortion of pressed pulp fibers having the ers 'Y thereof running in all directions, and a reinyforcing, laminated la er forA said inner body '1 portion formed ofwa liber sheet Wound about said inner body y portion, the fibers ofisaid sheet disposed to run lengthwise andaxially of the conduit, the majority of the fibers rrimaxially of tle conguitmx v Y testimon w ereo a my signature. 1 ivILLIAM G. JOHNSON. 

